Discovery of an Extended γ-Ray Emission around the Supernova Remnant Candidate Associated with PSR J0837-2454

Motivated by the recent discovery of a low-surface-brightness diffuse emission, a supernova remnant (SNR) candidate, surrounding the young pulsar PSR J0837-2454, we carry out a likelihood analysis of the γ-ray data obtained by the Fermi Gamma-ray Space Telescope from 2008 August to 2022 November. Using a 2D Gaussian spatial template, we detect a significant extended γ-ray emission with a 68% containment radius of ~1.°8, which is spatially coincident with the new SNR candidate at the ~12σ confidence level. The spectrum of the extended γ-ray emission, obtained in the energy range of 0.1-500.0 GeV, shows a significant spectral curvature at ~1 GeV, with a log-parabola spectral shape. Several scenarios, such as an SNR, pulsar wind nebula, and pulsar halo, are discussed as the potential origins of the extended γ-ray emission, and our model fitting results are preferred for the SNR scenario.